The present invention relates to the liquid supply assemblies that supply mixtures of component liquids to be sprayed (e.g., paint) to gravity feed liquid spraying devices such as spray guns.
Various liquid supply assemblies have been described for supplying mixtures of component liquids to be sprayed to gravity feed liquid (e.g., paint) spraying devices such as spray guns, including the supply assembly having a collapsible liner that is described in International Publication Number WO 98/32539 of Jul. 30, 1998, the content whereof is incorporated herein by reference, and the improvement in that supply assembly described in U.S. patent application Ser. No. 09/901,410 filed Jul. 9, 2001, the content whereof is also incorporated herein by reference.
The liquid supply assembly described in WO 98/32539 includes a container of stiff polymeric material comprising a side wall and a bottom wall at a bottom end of the side wall with an opposite top end of the side wall defining an opening into a cavity in the container, and a flexible liner within that cavity, which liner corresponds in shape to an inner surface of the container, and has an annular lip along the top end of the side wall that defines an opening into a cavity in the liner. That liquid supply assembly further includes an adapter assembly comprising a central portion having a through opening that is adapted to engage the inlet port of the gravity feed liquid spraying device, a transverse portion including a peripheral part adapted for engagement within the flexible liner adjacent the top end of the container, and means for securing the flexible liner around that peripheral part of the adapter assembly. The flexible liner within the cavity in the container can be used as a receptacle for measuring and mixing two or more component liquids for the mixture to be sprayed, and markings or indicia are provided on the side of the container that enable the volume of the contents of the container to be determined, which can facilitate measuring the needed amounts of those component liquids. After the liquids are mixed the adapter assembly is secured to the flexible liner, the adapter assembly is engaged with the inlet port of the spraying device, the liquid supply assembly is positioned above the spraying device with the bottom wall of the container uppermost, and the spraying device is operated to dispense the liquid mixture from within the flexible liner. The flexible liner collapses as the liquid mixture is dispensed to restrict the formation of a vacuum in the liner.
U.S. patent application Ser. No. 09/901,410 describes a liquid supply assembly for use with gravity feed liquid spraying devices that, like the liquid supply assemblies described in WO 98/32539, provides indicia by which component liquids for mixtures of liquids to be sprayed by such devices are measured to provide predetermined ratios, but which affords conveniently providing indicia that facilitates measuring many more of the different ratios of different component liquids that might be desired by operators of such liquid spraying devices than when such indicia are provided on the containers or mixing cups as described in WO 98/32539 by providing different indicia on a plurality of different indicating sheets of resiliently flexible polymeric material, any one of which sheets can be positioned between the side wall of the container and the flexible liner.
A liquid supply assembly for use with gravity feed liquid spraying devices incorporating features described in WO 98/32539 and in U.S. patent application Ser. No. 09/901,410 is currently being sold by Minnesota Mining and Manufacturing Company under the trade designation xe2x80x9c3M (T.M.) Paint Preparation Systemxe2x80x9d. That liquid supply assembly is adapted to contain a fairly large amount of liquid (i.e., about 20 fluid ounces or 600 ml) and incorporates several disposable parts that are typically discarded rather than being cleaned after liquid is sprayed from them. While use of that liquid supply assembly is economical when a large surface area is to be sprayed because of the short clean up time afforded by its disposable parts, it becomes less economical when only a small amount of liquid is to be sprayed, such as, for example, when a painter is testing a paint mixture for a color match, or is painting a small surface area, or is spraying a thinned clear coat or blending clear to blend new and old layers of clear coat. Painters reportedly have mounted only the disposable first adapter 40 described in U.S. patent application Ser. No. 90/901,410 in the reusable second adapter 54 on their spray guns (without the container 12, disposable liner 20 and sealing ring 53) with its peripheral part 50 uppermost to contain a small amount of paint to be sprayed for such purposes in the cavity defined by its then upwardly diverging frusto conical upper surface. Such use of the first adapter 40 is difficult, however, in that its peripheral part 50 must be kept generally horizontal to prevent spilling the paint, and even then, the first adapter 40 has a very large opening through which paint can spill if the spray gun or adapter 40 is bumped or moved sideways too suddenly.
The present invention provides an economical and easily usable liquid supply container for a small amount of liquid to be sprayed by a gravity feed spraying device such as a spray gun.
According to the present invention there is provided a small volume container for use to feed liquid to a gravity feed liquid spraying device. The container comprises a body portion having axially spaced first and second ends, means for closing the second end of the body portion, and a first adapter attached to the first end of the body portion. The body portion, means for closing, and first adapter have inner surfaces defining a small volume cavity in the container (i.e., a cavity having a volume in the range of about 0.5 to 5 ounces or 15 to 150 ml). The first adapter comprises an engagement portion having a through opening communicating with the cavity in the body portion, which engagement portion is adapted for liquid and air tight engagement with the spraying device. The container also includes means for restricting the formation of a vacuum in its cavity as liquid moves out of its cavity through the first adapter with the second end of the container uppermost.
The engagement portion of the container according to the present invention can be adapted for engagement with the reusable second adapter 54 that can be attached to a spraying device that is described in U.S. patent application Ser. No. 90/901,410.
In one embodiment of the small volume container the body portion is formed by thin flexible polymeric material, and the container further includes a plurality of stiff rings fixed to and spaced axially along the body portion. That container can be filled with liquid by manually collapsing the body portion of the container between the rings to decrease the size of the cavity in the container, immersing an end portion of a transfer pipette engaged with the inner surface of the engagement portion of the first adapter in the liquid, and pulling the second end of the body portion away from its first end to expand the volume of the cavity in the container so that atmospheric pressure pushes liquid into that cavity through the pipette. The body portion is again collapsible between the rings to afford movement of the rings to positions closely adjacent to each other to decrease the volume of the cavity as liquid in the container moves through the opening in the first adapter into a spraying device, thereby providing the means for restricting vacuum in the cavity.
In another embodiment of the small volume container the body portion is formed by thin flexible polymeric material, and the container further includes a fastener closing the second end of the body portion, which fastener is separable to open the second end of the body portion and facilitate filing the container with liquid through the second end of the body portion. The body portion is collapsible as liquid in the container moves through the opening in the first adapter to provide the means for restricting vacuum in the cavity.
In another embodiment of the small volume container the body portion comprises a stiff body part having an first end defining the first end of the body portion and an opposite second end, and a flexible part formed by thin flexible polymeric material extending from the second end of the stiff body part and defining the second end of the body portion. The adapter includes a cap-like portion fixed to the end of the engagement portion adjacent the body portion, which cap-like portion releasably engages the first end of the stiff body member in liquid tight engagement, and is separable from the stiff body part to open the first end of the body portion and facilitate filing the cavity with liquid through that first end. The flexible part of the body portion is collapsible as liquid in the container moves through the opening in the first adapter to provide the means for restricting vacuum in the cavity.
In another embodiment of the small volume container the body portion is formed of stiff resiliently flexible polymeric material that upon being collapsed by application of outside force and then released will return to its original shape. The container is capable of being filled with liquid by manually collapsing the container, immersing an end portion of a transfer pipette engaged with the inner surface of the engagement portion of the first adapter in the liquid, and allowing the container to return to its original shape to expand the volume of the cavity in the container so that atmospheric pressure pushes liquid into that cavity through the pipette. The body portion of the container is again collapsible as liquid in the container moves through the opening in the first adapter into the spray gun to provide the means for restricting vacuum in the cavity.
In another embodiment of the small volume container the elongate body portion is formed of stiff polymeric material and has an annular lip at its second end. The means for closing the second end of the body portion is a cap releasably engaging the second end of the body portion, which cap is separable from the body portion to thereby open the second end of the body portion and facilitate filing the cavity with liquid through that second end. The means for restricting vacuum in the cavity can be provided by loosening the cap when the liquid is being sprayed, or by providing a vent opening in the cap.
In another embodiment of the small volume container the body portion and the adapter are provided by the disposable first adapter 40 described in U.S. patent application Ser. No. 90/901,410 (without the container 12, disposable liner 20 and sealing ring 53) including its peripheral part 50 which, as discussed above can contain a small amount of liquid to be sprayed in the cavity defined by its diverging frusto conical inner surface and its peripheral part 50. The means for closing the second end of the body portion is a cover (i.e., a polymeric cover of the type used to close opened cans of coffee) that releasably engages the outer surface of that peripheral part 50. That cover also has or can be provided with a vent opening into the cavity to provide the means for restricting vacuum in the cavity.
The embodiments of the small volume container described herein are of a sufficiently inexpensive structure that they can be disposed of after a single use, however, certain of the embodiments could be cleaned and re-used if that was desired.